Soluble oil composition for use in lubricating compositions



United States Patent 3,412,023 SOLUBLE OIL COMPOSITION FOR USE IN LUBRICATIN G COMPOSITIONS Charles L. Zuraw, Harvey, Ill., and David B. Sheldahl, Griflith, Ind., assignors to Sinclair Research, Inc., New York, N .Y., a corporation of Delaware No Drawing. Filed Mar. 1, 1967, Ser. No. 619,582 9 Claims. (Cl. 25233.2)

ABSTRACT OF THE DISCLOSURE A soluble oil composition which forms stable emulsions when mixed with substantial amounts of water and which contains a major amount (e.g. about 85 to 95 wt. percent) of mineral lubricating oil, a small amount (eg, about 1 to 3 Wt. percent) of water, at least about 0.1 wt. percent of an alkyl sulfo-amide (e.g. having the structure (I? CH percent.

This invention relates to improved soluble oil compositions containing anionic emulsifying systems. More particularly, this invention pertains to improved hydrocarbon-based emulsifiable oils containing a combination of certain anionic emulsifying agents which provides a prodnet of exceptional properties.

Soluble oils are used, for example, as cutting, spraying and grinding oils in metal machining operations and generally contain, besides the base hydrocarbon oil, a small amount of water, one or more emulsifiers and often, certain optional additives such as corrosion or rust inhibiting agents, coupling agents, bactericides, etc. In use, the soluble oils are generally mixed with a substantial quantity of water and applied as an emulsion, e.g. of the oil-in- Water type. Soluble oils employing anionic emulsifying systems have generally proved difficult to emulsify with cold hard water. Curds usually are formed which do not disperse easily without appreciable agitation resulting in considerable inconvenience to users of the oils in colder climates and where unsophisticated stirring methods are used.

We have now found a soluble oil composition containing a combination of certain anionic emulsifying agents which composition has a reduced tendency to form curds with cold, hard water. Moreover, a savings in the amount of emulsifier required to effect a stable emulsion is realized employing the combination of emulsifying agents of the invention, since the combined amount required is less than the amount necessitated to effect an equally stable emulsion when any of the emulsifiers employed in the oils of the invention is used alone.

The soluble oils of the invention contain a mineral lubricating oil as the major component, a small, minor amount of water, and a combination of (A) an alkyl sulfo-amide of a carboxylic acid and (B) an oil-soluble, aromatic ammonium or alkali metal sulfonate or an oilsoluble alkali metal or ammonium salt of an aliphatic monocarboxylic acid. Since the soluble oils of the present invention may be used in diverse industrial operations, the exact proportions of the various ingredients may vary 3,412,023 Patented Nov. 19, 1968 according to the specific operation in which the soluble oil will be used. Ordinarily, however, the soluble oil will include about to 95, preferably at least 87 weight percent mineral lubricating oil base; a small, stabilizing amount, for instance, about 1 to 3 weight percent of water; about 4 to 12, preferably about 4 to 6 total weight percent of the A and B emulsifying components designated above. Frequently, the oil will contain a minor amount, e.g. about 1 to 3 weight percent, of one or more coupling agents, which may be organic oxygen-containing compounds. Other ingredients such as bactericides, foam inhibitors, extreme pressure agents, etc., may be present in the soluble oil, for example, in amounts of about 1 to 10 percent by weight.

The alkyl sulfo-amide of a carboxylic acid component of the composition of the invention has the following structure:

wherein R is hydrogen or a lower alkyl group, R is hydrogen or a hydrocarbon radical of 1 to about 20 carbon atoms, e.g. methyl, ethyl, propyl, butyl, amyl, hexyl, cyclohexyl, phenyl, octyl, linoleyl, stearyl, etc. R is an aliphatic, including cycloaliphatic, hydrocarbon containing at least 6, preferably 12 to 22, carbon atoms, and X is an alkali metal, e.g. sodium, potassium, etc., or alkaline earth metal, e.g. calcium, magnesium, etc. The acyl radical in the above formula may be straight or branched chain, saturated or unsaturated, and, if desired, may contain non-deleterious substituents. The acyl radical may be a residue of such acids as oleic acid, stearic acid, palmitic acid, linoleic acid, linolenic acid, ricinoletic acid, monohydroxy stearic acid, lauric acid, high molecular weight naphthenic acids, fatty acids obtained from the oxidation of petroleum waxes, and the like. The fatty acid residues can be obtained from vegetable oils and animal fats such as soybean oil, coconut oil, lard oil, corn oil, castor oil, tallow and the like. Other carboxylic acid residues having the desired number of carbon atoms are the acid residues obtained from tall oil which contains a mixture of fatty acids and resin acids.

The oil-soluble aromatic sulfonates that may be used in the composition of the invention include the alkali metal and ammonium salts of aromatic oil-soluble sulfonic acids, preferably the oil-soluble sodium soaps of sulfonic acids derived from petroleum hydrocarbons, as for example the sodium mahogany sulfonates, obtained as a result of treating a mineral lubricating oil fraction or other liquid petroleum hydrocarbon with concentrated or fuming sulfuric acid, or sulfur trioxide, followed by neutralization thereof with sodium hydroxide or the like. Although their exact general structure may vary, it appears that these sulfonates are composed to a large extent of aromatic hydrocarbons having either one or two aromatic rings per molecule possible with one or more long-chain alkyl groups containing from about 8 to 24 or more carbon atoms attached to the ring nuclei. However, other useful aromatic sulfonates are the synthetic aromatic sulfonates prepared from sulfonic acids, e.g. substituted naphthalenes and benzenes, by the reaction of paraffin chains of 8 to 24 or more carbon atoms with aromatic nuclei which are then sulfonated with fuming sulfuric acid followed by neutralization with sodium hydroxide. To obtain good results, we use a sodium mahogany sulfonate obtained from acid-treating a coastal lube oil, for example, with a viscosity of about 100 to about 2,000 SUS at 100 F. The sulfonates may be used as about 10 to percent concentrates in a mineral oil, for instance, of a lubricating oil base. The sul'fonate may have an average molecular weight of about 350 to 500' although we prefer a range in between about 400 and 500. To get excellent results, we can use a sulfonate with an average molecular weight of about 4430 to 4450 and in an amount of about 50 to 70 percent (dry basis) in a mineral oil.

Suitable aliphatic monocarboxylic acid salts include the alkali metal and ammonium salts of these acids, preferably the alkali metal and ammonium salts of olefinically-unsaturated acids, of about 12 to 20, preferably about 16 to 18 carbon atoms. Some examples of suitable acid salts are the alkali metal and ammonium salts of such fatty acids as lauric, stearic, palmitic, oleic, linoleio, eleostearic, etc.

The amounts of each of the above described anionic emulsifying agents A and B employed in the oils of the invention is at least about 0.1% of A and at least about 2% of B, with the total of A plus B being 4 to 12%. Preferably, about 0.1 to 1 weight percent of the alkyl sulfoamide component is combined with about 3.2 to Weight percent of the aromatic sulfonate when the sulfonate is employed as the B component, or with about 4 to 6.5 weight percent of the monocarboxylic acid salt when such is present. Highly advantageous quantities are about 0.2 Weight percent of the alkyl sulfo-amide with either about 4.8 weight percent of the aromatic sulfonate or about 5.8 weight percent of the monocarboxylic acid salt.

Thus, where the resulting emulsion is to be used as a lubricant for grinding operations, for example, it has been found that about one part of the oil for each 20 to 100 parts of water, and particularly one part of the oil to 40 or 60 parts of water, produces very satisfactory results. For use in quenching operations, emulsions formed with one part of soluble oil per 10 to parts of water have been found to be very advantageous. As a rolling mill oil, emulsions containing one part of the composition for each 1 0 to 30 parts of water effect very desirable results.

The following example is included to further illustrate the present invention and is not to be considered limiting.

EXAMPLE Several soluble oil compositions A to I listed in Table I were tested for emulsion stability by mixing 5 cc. of the soluble oil composition with 95 cc. distilled water in a 100 cc. graduate and observing the emulsion after 24 hours. Blends B and E are soluble oil compositions of the present invention. The alkyl sulfo-amide used in Blends B, E, G, H and :I had the general structure described above wherein X is sodium, R is hydrogen, R is methyl, and R is a hydrocarbon derived from tall oil acid containing about 16 to 20 carbon atoms. The results of the tests are listed in Table I.

TABLE I.SOLUBLE OIL EMULSION STABILITY Sodium Potassium Alkyl Mineral Petroleum Oleate, Sulfoamide, Hexylene Water, Composition Oil Sultonate, Percent Percent Glycol, Percent 2 mm. Cuff Percent 3 Percent (Dry Soap) (Dry Soap) Percent 2 (Dry Soap) 1.0 2. 0 2 Cream. 1. 0 2. 0 0. 1.0 2.0 5 Yelolw (Trace Oil). 2. 10 1. 2 Cream. 2. 10 1. 40 Do. 2.10 1.40 4 Yellow (Oil). 1.50 1. 2 Cream. 1. 50 1. 50 4 Cream} 1. 50 1. 50 6 Yellow.

1 Emulsion thin and watery.

a viscosity of 100 SUS at 100 F.

The oils used as the base and major component in the emulsifiable oils of the present invention are mineral lubricating oils. The oils used include the petroleum lubricating oils such as refined coastal oils and refined Mid- Continent oils. The oils may be refined by acid-treatment, solvent extraction, hydrogenation or other procedures. Although various oils of lubricating viscosity can be used in the products of our invention, it is preferred to use a substantially anhydrous lubricating oil with a viscosity from about 50 to l, 200 SUS at 100 F., preferably 50 to 150 SUS at 100 F. We have had good results with a hydrogen 'refined coastal oil with a viscosity of about 100 SUS at 100 F.

As aforementioned, a coupling agent is often employed in the oils of the invention. The function of such an agent is to couple the aqueous portion of the neat soluble oil to the continuous oil phase to give a clear product and also to couple the neat oil to diluent water added to provide an emulsified soluble oil suitable for use. Among the wellkno-wn coupling agents usable in the composition are the aliphatic ether-alcohol compounds containing from about 1 to 30 carbon atoms, for instance, diethylene glycol; the ether complexes of ethyl Cellosolves, Carbitol, and butyl Cellosolve; the polyether glycols with terminal ether groups; and the polyoxyalkylene glycols, as well as ethylene glycol, propylene glycol, hexylene glycol, etc. One or more of the above coupling agents can be used either alone or in mixtures, and in various amounts, for instance, about 0.5 to 5, preferably about 1 to 3, weight percent may be employed.

In use as soluble oil emulsions the compositions of this invention are frequently dispersed in about 5 to 100 or more parts of water per part of the oil compositions, depending upon the particular application contemplated.

2 Each soluble oil system, depending on soaps used, require difierent amounts of water and coupler to produce a balanced soluble oil, i.e., one that permits maximum utilization of soap.

3 Hydrorefined coastal oil having The data listed in Table I show that none of the emulsifiers of the present invention used alone in a concentration equal to the total weight of the combination of the emulsifiers of the present invention will provide an emulsion of comparable stability to that of Blends B and E.

What is claimed is:

1. An emulsifiable oil composition comprising a mineral lubricating oil base as the major component, a small, emulsion stabilizing amount of water, at least about 0.1 weight percent of (A) an oil-soluble alkyl sulfo-amide having the structural formula:

wherein R is selected from the group consisting of hydrogen, and lower alkyl, R is selected from the group consisting of hydrogen and hydrocarbon of 1 to about 20 carbon atoms, R is aliphatic hydrocarbon containing about 6 to 22 carbon atoms and X is selected from the group consisting of alkali and alkaline earth metals, and at least about 2 weight percent of (B) a salt selected from the group consisting of an oil-Soluble alkali metal or ammonium aromatic sulfonate and an ammonium or alkali metal salt of an aliphatic monocarboxylic acid of about 12 to 20 carbon atoms, wherein the total amount of A plus B in the oil is about 4 to 12 weight percent.

2. The composition of claim 1 to which is added about 1 to 3 weight percent of a coupling agent.

3. The composition of claim 2 wherein said salt is a sodium mahogany sulfonate.

4. The composition of claim 2 wherein said salt is potassium oleate.

5. The composition of claim .9 containing said alkyl sulfo-amide wherein X is an alkali metal, R is hydrogen, R is methyl and R 00 is acyl derived from tall oil acid.

6. The composition of claim 4 containing said alkyl sulfo-arnide wherein X is an alkali metal, R is hydrogen, R is methyl and R CO is acyl derived from tall oil acid.

7. An emulsifiable oil composition comprising a mineral lubricating oil base with a viscosity of about 50 to 150 SUS at 100 F. as the major component; about 1 to 3 weight percent Water; about 1 to 3 weight percent of hexylene glycol; a member selected from the group consisting of about 3.2 to 5 Weight pe cent of an oilsoluble sodium petroleum sulfonate and about 4 to 6.5 weight percent of a potassium salt of an aliphatic monocarboxylic acid of about 16 to 18 carbon atoms; and about 0.1 to 1 weight percent of an oil-soluble alkyl sulfol amide of a carboxylrc acid havmg the structural formula:

UNITED STATES PATENTS 9/1964 Broussalian et al. 260507 10/1965 Blake et al. 25233.3

DANIEL E. WYMAN, Primary Examiner.

P. H. FRENCH, Assistant Examiner. 

